Heat exchanger



2 Sheets-Sheet 1 Mil/[N708 HEAT EXCHANGER Filed Jan. 25, 1935 W. J. BLANCHARD Aug. 13, 1935.

Aug. 13, 1935 w. J. BLANCHARD I 2,011,032

HEAT ,EXCHANGER Filed Jan. 23, 1935 7 2 Sheets-Sheet 2 M/VE/V TOR Patented Aug. 13,. 1935 UNITED" STATES PATENT OFFICE lnGreat Britain March 9, 1934 1 Claims- (Cl. 251-19) The present invention relates to heat exchangers and more particularly to devices of this character suitable for use as cry'stallizers in sugar manufacture. The invention however is not limited to this application and can be used for various other purposes, some of which are hereinafter specified. e

An object of the present invention is to provide a heat exchanger with rug ed construction and simple design which will be easy to maintain in good order and to keep clean.

Another object of the invention is to provide a heat exchanger in which a mass to be treated gray be cooled or heated uniformly throughout its ulk;

A further object 01 the invention is to provide a heat exchanger in which both the treating material and the mass to be treated are agitated.

Still another object of the invention is to provide a heat exchanger in which the entire bulk of the mass to be treated will be traversed by the treating material.

Other objects of the invention will be apparent from the following description as it proceeds.

The heat exchanger comprises an outer container and a rotatable inner container in the form of a drum having a series of outwardly projecting tubes disposed along its length in such a manner that the paths swept out by successivetubes overlap.

' More specifically the heat exchanger comprises two concentric drums, the outer one of which is fixed, the inner drum being rotatable and provided with a series of tubes commimicating at their inner ends with the interior thereof and closed at their outer ends, said tubes projecting radially outward from said inner drum towards the outer drum and being so disposed that the paths swept out by successive tubes overlap.

The two drums are preferably cylindrical and concentric, the inner rotatable drum being mounted on. journals supported at the axis of the outer drum, and these journals may comprise stuiling boxes providing fluid tight bearings.

According to a feature of the invention treating fluid is supplied to and led out from the inner rotating drumby way of axial conduits provided in the supporting trimnions. The fiow of fluid therethrough may be controlled at one or both ends by suitable valves.

Theinnerdrmnmayberotatedbyanygearing such as a worm gearing,

' Access is preferably provided to the interior of 'theinnerdrumbywayof manholes normally closed hv suitable covers, wher by cleaning revolution of the container as the interior thereof is made possible. Moreover means may be provided for automatically cleaning the interior and exterior surfaces of the inner drum and the tubes connected thereto.

The axes or the common axis of the containersmay conveniently be arranged horizontally or nearly so whereby, it the inner container is partially filled with liquid, the projecting tubes along the whole length thereof will be emptied at each they are raised above the horizontal axis. 1

According to a modification of the invention the two drums may be arranged to rotate together as a single unit.

In order that the invention may be more clearly understood an embodiment thereof will now be described with reference to the accompanying drawings in which:

Fig. 1 is a sectional longitudinal elevation,

' Fig. 2 is an end view in part broken away, and

Fig. 3 is a transverse section of a heat exchanger constructed according to the invention.

Referring to the drawings, the heat exchanger comprises an outer drum I mounted on a supporting framework 2. The end walls of the drum are reinforced by the girders 3, and carry at their centres journals 4 and 5 through which pass respectively the trunnions i and l. The journals 4 and 5 are shown as comprising a simple form of stufilng box, but of course, any suitable construc- 36 tion may be employed.

The trimnions i and 1 support between them an inner drum 8 from which project the tubes 9 which, as will be seen from Fig. 1, are arranged around the drum in'a spiral formation and so that the paths they sweep out as they rotate overlap. In the arrangement shown, the paths overlap by one half the width of a tube, but it will be understood of course that the extent of overlap maybe greater or less as may be found most suit ablefor the work contemplated. The trlmnion I at its outer end seats upon a thrust bearing III which is supp rt by a bracket from the drum I. All expansion therefore takes place away from this hearing and is provided for 455 at'the'other end of the machine. Keyed on the trunnion I is a worm wheel II which is engaged by a worm I! located on the shaft l3 which latter is supported in saddle bearings fixed on the girders I mounted on the end of the drum i. electric motor or any other suitable form of drive applied to the pulley i5 is employed to rotate the worm. 1 clutch mechanism of any suitable type maybeincorporatedinthe drive. Theworm l2 isshownasencasedinanoilbath i6 bymeans cl 5 which the worm mechanism is kept suitably lubricated.

Passing through the trunnion I is a conduit I! a fixed supply pipe l9. This pipe may be branched as shown, one branch being employed for the supply, say,"of cooling water, while the .other serves for the supply of steam. These branches may be controlled by the respective valves or cocks l9, and I9". Thestufling box I8 is shown supported on a framework 20, although of course any other supporting means which may be. more convenient may be employed.

At the other end of the machine the trunnion 6 is provided with an outlet conduit 2| controlled by a screw-down control valve 22 which may be adjusted by the hand wheel 23 according to requirements. The outlet from the conduit '2] feeds into the splash box 24 with which is connected the outlet pipe 25.

Access to the interior of the inner drum is pro- I vided by means. of the manholes 26 closed by suitable covers and preferably provided as shown one at each end of the drum. It is thus possible for a cleaner to enter the drum and clean the interior of the tubes 9 as well as the inner surface of the drum 8.

The tubes 9 may befastened to the inner drum 8 in any desired way, suitably by welding. The

ends of the tubes may be closed by caps or in any other suitable way but preferably by flattening and welding the flattened scam, the flat portion being arranged in the direction of the axis of the container. vAlternatively, it may be arranged obliquely so as to cause a feed of the material in the outer container and for this same purpose, if .desired, the tubes .themselves may be of flattened cross section and be arranged obliquely with refreence'to the axis of the container.

It will be understood of course that modification may be made in the construction of the ma-' chine withoutjdeparting from the scope of the present invention,- and according .to one such modification, the inner and outer drums may be arranged to revolve together as a single unit. It will be readily understood that .the operation of the machine in this way will be similar to the operation of the machine as above described. since i the rotation of the outer drum will not substantially affect the mass to be cooled.

In the operation ofthe machine as a sugar crystallizer, the massecuite from the vacuum pans is delivered hot intothe drum tby way of the chute 21,-while cold or warm water for the cooling or heating thereof is fed through the pipe l9 into the inner cylinder. fully opened, in which case, since the outlet is arranged on the central axis, the inner container will be maintained approximately half full of water. The actual level of the water in the inner container can however be regulated by suitable adjustment of the valve 22 or by the arrangement of a. suitable overflow or siphon at the outlet end,

but it is important that the hollowinterior of ly uniform cooling of the mass.

The valve 22 maybe cooled within the drum I will be traversed by the cooling tubes. Furthermore, the cooling water in the inner drum is in a constant state of agitation. which is continued through a stufiing box l8 to These two facts combine to produce an extremebatches of minute new crystals forming. This is particularly-desirable in sugar manufacture in order that the operation of separating the crystals from the mother liquor in'the centrifugal machines may be simplified. The larger the'crystals which are obtained the easier and more efficient is the subsequent separation and consequently the better the yield of sugar.

After the desired temperature in the crystallizer has been attained it'is usually found that the mother liquor is still supersaturated with sugar. Useful advantage of this fact can be taken by heating the mass by passing steam or hot water through the inner containerso as'to make the separation of the mother liquor from the sugar crystals more easyi'n the centrifugal separators.

mother liquor is still supersaturated.

Although the invention has been so far described particularly with reference to a crystallizer for sugar manufacture, it will be understood of course that many other,uses may be found for the machine. It may, for instance, be employed for heating a liquid in the inner container by passing steam or flue gases through the outer container or vice versa. If the device is to be used for heatin'gfa liquid in the inner container it is preferable not to flll this container completely, so that circulation of the liquid through the tubes is effected in the manner above described.

Where the apparatus has to be used for heating by passing steam through the inner container,

troughs may be, arranged inside this container to collect the condensate for discharging and which would thereby avoid accumulation thereof.

ever, to effect the cleaning automatically. For

example, the tubes could be kept clean on the outside by means of a ring. placed loosely aroundeach tube which slides up and down by its own weight during the rotation of, the inner container. Such a ring would best be madepliable, such as a ring of chain, and loosely fit around the tubes. This arrangement could be used for cleaning soot off the external surfaces of the tubes if the contents of the inner container are being heated by flue gases passed through the.

For cleaning the tubes internally, a

. No sugar is dissolved by this heating because the Y a drum and tubes on said inner drum radiating outinner container and would in the indefinitely, continuously moving in and out'of the various tubes to clean the same.

I claim:

1. Heat exchanger comprising a fixed outer drum, an inner drum, trunnions on said inner drum, journals mounted in the ends of said outer drum supporting said trunnions, conduits formed in said trunnions, the conduit at one end.

aifording communication between a liquid supply pipe and the interior of said drum, the conduit at the other end affording an outlet for liquid and tubes arranged on said inner. drum radi ating therefrom and disposed in spiral formation around said inner drum in such a manner that the paths swept out thereby as the inner drum rotates overlap.

2. Heat exchanger comprising a fixed outer drum, an inner drum, trunnions on said inner drum, journals mounted in the ends of said outer drum and tubes projecting from said inner drum,

said tubes being arranged in straight longltudinal rows, the tubes in successive rows bein displaced longitudinally by a distance equal one half the width of atube. a

3. Heat exchanger comprising a fixed outer drum, an inner drum, trunnions on said inner drum, journals mounted in the end walls of said outer drum supporting said trunnions. conduits formed in said trunnions, one of said conduits connecting a supply pipe with the interior of said inner drum, the other of said conduits affording an outlet from said inner drum, a control valve regulatingsaid outlet, said inner drum comprisv mg tubes projecting radially outward therefrom and arranged in spiral formation thereon in such a manner that the paths swept out thereby as they rotate' overlap. 1

4. Heat exchanger comprising a fixed outer drum, an inner drum, trunnions on said inner drum, journals mounted in the end walls of said outer drum supporting said trunnions,-conduits formed in said trunnions, one of said conduits connecting a supply pipe with the interior of said inner drum, the other of said'condults affording an outlet from said inner*drum,-;a control valve regulating said outlet, a splash box encasing said outlet and the control valve therefor, said inner drum comprising tubes projecting radially outward therefrom and arranged in spiral formation thereon in such a manner that the paths swept out thereby as they rotate, overlap.

5. Heat exchanger comprising a fixed outer drum an inner drum, trunnions on said inner drum, journals mounted in the ends of said outer drum supporting said trunnions, one of said trunnions engaging a thrust hearing by which longitudinal movement thereof is limited, clearance to accommodateexpansion between the ends of said inner and outer drums at the other end of the a machine, and tubes on said inner drum projecting radially outward therefrom, and so arranged thereon that the paths swept out by said tubes as they rotate overlap. v a

6. Heat exchanger comprising a fixed outer drum an inner drum,.trunnions mounted on said inner drum journals mounted in the ends of said duits constitutin an'outlet from said inner I wardly therefrom, and arranged thereon .so that the paths swept out by said tubes as they rotate. overlap. I

7. Heat exchanger comprising a fixed outer drum an inner drum, trunnions mounted on said inner drum, journals mounted in the ends of said outer drum supporting said trunnions, a thrust bearing engaging one of said trunnions and lim-' i trunnions, the conduit atone end affording communication between a liquid supply pipe and the interior of said drum, the conduit at the other end aii'ording an outlet for liquid; and tubes arranged-on said inner drum radiating outwardlytherefrom, successive tubes in the direction'of rotation being spaced in the longitudinal direction bya distance that is less than the diameter of a tube.

9. Crystallizer comprising a fixed outer drum, an inlet for hot solution in said drum, an inner drum, trunnions mounted on said inner drum, journals mounted in the ends 01. said outer drum supporting said trunnions, an inlet conduit for cooling water passing through one of said trunnions through which water is supplied to the interior of said inner drum, tubes communicating with the interior of said inner drum and radiating outwardly therefrom,

said tubes being closed at their outer ends and being arrangedfon said drum withsuccessive tubes in the direction of rotation longitudinally displaced by a' distance less than the diameter of a tube, an outlet conduit for said cooling water passing through the other said trunnion, and means for controlling the mean level of the cooling fluid in said inner drum,

10. Crystallizer comprising afixed outer drum constituting a container for hot solution, an

inner drui'n mounted on hollow trunnions journalled in the ends of said outer (111131,11183115' comprising said hollow trunnions for passing treating fluid through said inner rotatable drum,

a series of tubes radiating from said inner rotatable drum outwardly towards said outer container, said tubes communicating at their inner ends with the interior of the inner drum,. and being disposed on said inner drum with the axes of successive tubes longitudinally displaced along said inner drum by a distance less than the diameter of a tube, and means for rotating said innen drum, whereby said tubes are'passed through the hot solution in said outer drum to traverse the whole volume thereof in a single revolution of said inner drum.

11. Crystallizer comprising a fixed outer drum constituting a container for hot solution, an inner drum mounted on trunnions journalled in the ends of said outer drum, conduits passing through said trunnions, the conduit at one end constituting an inlet for cooling water and the conduit at the other end constituting an outlet for said water, means for-controlling the flow of water through said inner drum, and a series of tubes projecting radially outwards from said inner drum, said tubesbeing arranged onsaid inner drum with successive tubes longitudinally spaced by a distance less than the diameter of a. tube, said tubes communicating at their inner ends with the hollow interior .of said inner drum and being closed at their outer ends, said tubes constituting a container for hot solution, an inner drum mounted on trunnions journalled in the ends of said outer drum, conduits passing throlmh said trunnions, the conduit at one end constituting an inlet for cooling water and the conduit at the other end constituting an outlet for said water, a screw-down valve controlling said outlet conduit, and a series of tubes projecting radially outwards from said inner drum, said tubes being arranged on said inner drum with-successive tubes longitudinally spaced by a. distance less than the diameter of a tube, said tubes communicating at their inner ends with the hollow interior of said inner drum and being closed at their outer ends, said tubes moreover extending from said inner drum substantially to the inner surface of said outer drum, and means for rotating said inner drum, whereby substantially the entire mass of solution to be cooled is traversed by said tubes in a single revolution of said inner drum.

WALTER JOSEPH BLANCHARD. 

